The present invention relates to a linear device.
More particularly, it relates to a linear device which has a first, essentially rod-shaped functional unit and a second functional unit that at least partially encompasses the rod-shaped functional unit; and are able to move in relation to each other by means of at least one endless rolling element track, which includes a load-bearing rolling element channel segment, a return channel segment, and two deflecting channel segments that connect the load-bearing rolling element channel segment and the return channel segment to each other; the second functional unit has a main body and at least one end plate unit, which rests with a contact surface against an end surface of the main body and contains a deflecting channel segment of the rolling element track; and a lubrication groove, which is open toward the contact surface and extends at least partially in the circumference direction around the rod-shaped functional unit, is provided in the end plate unit.
Although the present invention is described below mainly in connection with the example of a linear guide device with a guide rail as the rod-shaped functional unit and a guide carriage as the functional unit that at least partially encompasses the guide rail, it should be noted at this point that the present invention can also be advantageously used in other types of linear devices such as rolling element bushing guides, in particular ball bushing guides, spline shaft guides (also often referred to in the trade as “ball splines”), or linear drive units such as rolling element linear drives, in particular ball-type linear drives.
The at least one end plate unit is usually attached to the main body with screws. It can, however, also be attached to the main body by means of detent elements.
Usually, the at least one end plate unit is provided with a lubricant supply connection in order to be able to supply lubricant to the rolling elements contained in the at least one rolling element track. The prior art has already proposed numerous designs for preventing lubricant from coming out of the lubrication groove, which is open toward the contact surface of the end plate unit against the main body, and escaping between the main body and the end plate unit.
One design known from U.S. Pat. No. 4,850,720, has proposed providing sealing lips, which protrude slightly from the contact surface of the end plate unit immediately adjacent to the lubrication groove. In the linear device known from U.S. Pat. No. 5,139,347, corresponding sealing lips are provided at the edge of the end plate unit.
By contrast, EP 1 416 178 A2, which defines the species, has proposed embodying the entire contact surface of the end plate unit against the main body as a domed surface and attaching the end plate unit to the main body by means of four fastening screws situated in the corners of the contact surface. EP 1 416 178 A2 is based on a prior art in which the end plate unit was attached to the main body by means of only two fastening elements, which made it impossible to prevent a gap formation between the end plate unit and the main body and the attendant danger of an undesired escape of lubricant between the end plate unit and main body. The desired sealing action could only be reliably assured through the domed embodiment of the contact surface and the use of four fastening screws, i.e. the embodiment according to EP 1 416 178 A2.